/*----- Header files ------------------------------------------------------*/
-#include <ctype.h>
-#include <errno.h>
-#include <stdio.h>
-#include <string.h>
-#include <string.h>
-
-#include <sys/types.h>
-#include <unistd.h>
-
-#include <arpa/inet.h>
-
-#include <syslog.h>
-
-#include <mLib/dstr.h>
-
-/*----- Data structures ---------------------------------------------------*/
-
-union addr {
- struct in_addr ipv4;
- struct in6_addr ipv6;
-};
-
-struct socket {
- union addr addr;
- int port;
-};
-
-enum { L, R, NDIR };
-
-struct query {
- int af;
- struct socket s[NDIR];
-} query;
-
-#define RESPONSE(_) \
- _(ERROR, U(error, unsigned)) \
- _(UID, U(uid, uid_t)) \
- _(NAT, U(nat, struct socket))
-
-#define ERROR(_) \
- _(INVPORT, "INVALID-PORT") \
- _(NOUSER, "NO-USER") \
- _(HIDDEN, "HIDDEN-USER") \
- _(UNKNOWN, "UNKNOWN-ERROR")
-
-enum {
-#define DEFENUM(err, tok) E_##err,
- ERROR(DEFENUM)
-#undef DEFENUM
- E_LIMIT
-};
-
-enum {
-#define DEFENUM(what, branch) R_##what,
- RESPONSE(DEFENUM)
-#undef DEFENUM
- R_LIMIT
-};
-
-struct response {
- unsigned what;
- union {
-#define DEFBRANCH(WHAT, branch) branch
-#define U(memb, ty) ty memb;
-#define N
- RESPONSE(DEFBRANCH)
-#undef U
-#undef N
-#undef DEFBRANCH
- } u;
-};
+#include "yaid.h"
/*----- Static variables --------------------------------------------------*/
-static const char *errtok[] = {
+const char *const errtok[] = {
#define DEFTOK(err, tok) tok,
ERROR(DEFTOK)
#undef DEFTOK
};
static int parseaddr4(char **pp, union addr *a)
- { a->ipv4.s_addr = strtoul(*pp, (char **)pp, 16); return (0); }
+ { a->ipv4.s_addr = strtoul(*pp, pp, 16); return (0); }
static int addreq4(const union addr *a, const union addr *aa)
{ return a->ipv4.s_addr == aa->ipv4.s_addr; }
+static int parseaddr6(char **pp, union addr *a)
+{
+ int i, j;
+ unsigned long y;
+ char *p = *pp;
+ unsigned x;
+
+ for (i = 0; i < 4; i++) {
+ y = 0;
+ for (j = 0; j < 8; j++) {
+ if ('0' <= *p && *p <= '9') x = *p - '0';
+ else if ('a' <= *p && *p <= 'f') x = *p - 'a'+ 10;
+ else if ('A' <= *p && *p <= 'F') x = *p - 'A'+ 10;
+ else return (-1);
+ y = (y << 4) | x;
+ p++;
+ }
+ a->ipv6.s6_addr32[i] = y;
+ }
+ *pp = p;
+ return (0);
+}
+
+static int addreq6(const union addr *a, const union addr *b)
+ { return !memcmp(a->ipv6.s6_addr, b->ipv6.s6_addr, 16); }
+
static const struct addrfamily {
int af;
const char *procfile;
int (*addreq)(const union addr *a, const union addr *aa);
} addrfamilytab[] = {
{ AF_INET, "/proc/net/tcp", parseaddr4, addreq4 },
- { AF_INET6, "/proc/net/tcp6", /*parseaddr6*/ },
+ { AF_INET6, "/proc/net/tcp6", parseaddr6, addreq6 },
{ -1 }
};
/*----- Main code ---------------------------------------------------------*/
-static void dputsock(dstr *d, int af, const struct socket *s)
+static int sockeq(const struct addrfamily *af,
+ const struct socket *sa, const struct socket *sb)
+ { return (af->addreq(&sa->addr, &sb->addr) && sa->port == sb->port); }
+
+int get_default_gw(int af, union addr *a)
{
- char buf[INET6_ADDRSTRLEN];
+ int fd;
+ char buf[32768];
+ struct nlmsghdr *nlmsg;
+ struct rtgenmsg *rtgen;
+ const struct rtattr *rta;
+ const struct rtmsg *rtm;
+ ssize_t n, nn;
+ int rc = 0;
+ static unsigned long seq = 0x48b4aec4;
+
+ if ((fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0)
+ die(1, "failed to create netlink socket: %s", strerror(errno));
+
+ nlmsg = (struct nlmsghdr *)buf;
+ assert(NLMSG_SPACE(sizeof(*rtgen)) < sizeof(buf));
+ nlmsg->nlmsg_len = NLMSG_LENGTH(sizeof(*rtgen));
+ nlmsg->nlmsg_type = RTM_GETROUTE;
+ nlmsg->nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
+ nlmsg->nlmsg_seq = ++seq;
+ nlmsg->nlmsg_pid = 0;
+
+ rtgen = (struct rtgenmsg *)NLMSG_DATA(nlmsg);
+ rtgen->rtgen_family = af;
+
+ if (write(fd, nlmsg, nlmsg->nlmsg_len) < 0)
+ die(1, "failed to send RTM_GETROUTE request: %s", strerror(errno));
- inet_ntop(af, &s->addr, buf, sizeof(buf));
- if (af != AF_INET6) dstr_puts(d, buf);
- else { dstr_putc(d, '['); dstr_puts(d, buf); dstr_putc(d, ']'); }
- dstr_putf(d, ":%d", s->port);
-}
+ for (;;) {
+ if ((n = read(fd, buf, sizeof(buf))) < 0)
+ die(1, "failed to read RTM_GETROUTE response: %s", strerror(errno));
+ nlmsg = (struct nlmsghdr *)buf;
+ if (nlmsg->nlmsg_seq != seq) continue;
+ assert(nlmsg->nlmsg_flags & NLM_F_MULTI);
+
+ for (; NLMSG_OK(nlmsg, n); nlmsg = NLMSG_NEXT(nlmsg, n)) {
+ if (nlmsg->nlmsg_type == NLMSG_DONE) goto done;
+ if (nlmsg->nlmsg_type != RTM_NEWROUTE) continue;
+ rtm = (const struct rtmsg *)NLMSG_DATA(nlmsg);
+
+ if (rtm->rtm_family != af ||
+ rtm->rtm_dst_len > 0 ||
+ rtm->rtm_src_len > 0 ||
+ rtm->rtm_type != RTN_UNICAST ||
+ rtm->rtm_scope != RT_SCOPE_UNIVERSE ||
+ rtm->rtm_tos != 0)
+ continue;
-static void logmsg(const struct query *q, int prio, const char *msg, ...)
-{
- va_list ap;
- dstr d = DSTR_INIT;
+ for (rta = RTM_RTA(rtm), nn = RTM_PAYLOAD(nlmsg);
+ RTA_OK(rta, nn); rta = RTA_NEXT(rta, nn)) {
+ if (rta->rta_type == RTA_GATEWAY) {
+ assert(RTA_PAYLOAD(rta) <= sizeof(*a));
+ memcpy(a, RTA_DATA(rta), RTA_PAYLOAD(rta));
+ rc = 1;
+ }
+ }
+ }
+ }
- va_start(ap, msg);
- dputsock(&d, q->af, &q->s[L]);
- dstr_puts(&d, " <-> ");
- dputsock(&d, q->af, &q->s[R]);
- dstr_puts(&d, ": ");
- dstr_vputf(&d, msg, &ap);
- va_end(ap);
- fprintf(stderr, "yaid: %s\n", d.buf);
- dstr_destroy(&d);
+done:
+ close(fd);
+ return (rc);
}
-static int sockeq(const struct addrfamily *af,
- const struct socket *sa, const struct socket *sb)
- { return (af->addreq(&sa->addr, &sb->addr) && sa->port == sb->port); }
-
-void identify(const struct query *q, struct response *r)
+void identify(struct query *q)
{
const struct addrfamily *af;
FILE *fp = 0;
char *p, *pp;
struct socket s[4];
int i;
+ int gwp = 0;
unsigned fl;
#define F_SADDR 1u
#define F_SPORT 2u
goto err_unk;
found_af:;
+ if (get_default_gw(q->af, &s[0].addr) &&
+ af->addreq(&s[0].addr, &q->s[R].addr))
+ gwp = 1;
+
if ((fp = fopen(af->procfile, "r")) == 0) {
logmsg(q, LOG_ERR, "failed to open `%s' for reading: %s",
af->procfile, strerror(errno));
if (af->parseaddr(&p, &s[0].addr)) goto next_row;
if (*p != ':') break; p++;
s[0].port = strtoul(p, 0, 16);
- /* FIXME: accept forwarded queries from NAT */
- if (!sockeq(af, &q->s[i], &s[0])) goto next_row;
- else continue;
+ if (!sockeq(af, &q->s[i], &s[0]) &&
+ (i != R || !gwp || q->s[R].port != s[0].port))
+ goto next_row;
}
if (uid != -1) {
- r->what = R_UID;
- r->u.uid = uid;
+ q->resp = R_UID;
+ q->u.uid = uid;
goto done;
}
next_row:;
if (!sockeq(af, &s[i^1], &s[i^2]) ||
!sockeq(af, &s[i^1], &q->s[R]))
continue;
- r->what = R_NAT;
- r->u.nat = s[i^3];
+ q->resp = R_NAT;
+ q->u.nat = s[i^3];
goto done;
}
strerror(errno));
goto err_unk;
}
+ logmsg(q, LOG_ERR, "connection not found");
}
#undef NEXTFIELD
err_nouser:
- r->what = R_ERROR;
- r->u.error = E_NOUSER;
+ q->resp = R_ERROR;
+ q->u.error = E_NOUSER;
goto done;
err_unk:
- r->what = R_ERROR;
- r->u.error = E_UNKNOWN;
+ q->resp = R_ERROR;
+ q->u.error = E_UNKNOWN;
done:
dstr_destroy(&d);
}
/*----- That's all, folks -------------------------------------------------*/
-
-int main(int argc, char *argv[])
-{
- struct query q;
- struct response r;
- char buf[INET6_ADDRSTRLEN];
-
- q.af = AF_INET;
- inet_pton(AF_INET, argv[1], &q.s[L].addr.ipv4);
- q.s[L].port = atoi(argv[2]);
- inet_pton(AF_INET, argv[3], &q.s[R].addr.ipv4);
- q.s[R].port = atoi(argv[4]);
-
- identify(&q, &r);
-
- switch (r.what) {
- case R_UID:
- printf("uid %d\n", r.u.uid);
- break;
- case R_ERROR:
- if (r.u.error < E_LIMIT) printf("error %s\n", errtok[r.u.error]);
- else printf("error E%u\n", r.u.error);
- break;
- case R_NAT:
- inet_ntop(q.af, &r.u.nat.addr, buf, sizeof(buf));
- printf("nat -> %s:%d\n", buf, r.u.nat.port);
- break;
- default:
- printf("unknown response\n");
- break;
- }
-
- return (0);
-}
~mdw / yaid / blobdiff